Apple has just seeded iPhone 2.1 beta 4 to developers-uninteresting, really, except for the fact that the push notification service has been pulled from the release "for further development." Targeted to hit your iPhone in September, the push service allows apps to receive notifications in the background while they're not running, a godsend for AIM and other messaging apps. Hopefully this doesn't mean it'll be delayed, but we've all learned what happens when iPhone software rolls out before it's finished baking, so I'd rather wait. [Mac Rumors]